The present invention relates to a resilient, liner insulation with a polymeric fiber insulation blanket core and to a method of making the resilient liner insulation. The resilient liner insulation exhibits a flame spread/smoke developed index per ASTM E-84-00a tunnel test of xe2x89xa625/50 and is especially suited for use as equipment and duct liner insulation for HVAC systems.
Glass fiber thermal and acoustical liner insulations are frequently used to line the equipment housings (the housings for air conditioning units, primary fans, etc.) and the air ducts of heating ventilating and air conditioning systems (HVAC systems) to control thermal and/or noise transmission through the walls of these housings and ducts. Glass fiber thermal and acoustical liner insulations are also frequently used to wrap or encase equipment such as dishwashers, refrigerators and other equipment where thermal and/or noise transmission must be controlled. While these glass fiber thermal and acoustical liner insulations perform very well and are quite cost effective when used for these applications, there may be certain applications where it would be desirable to use polymeric fiber liner insulations for lining equipment housings and/or ducts and for insulating appliances and other equipment.
However, to be considered for such applications, any polymeric fiber liner insulation must meet certain performance standards and be cost competitive with the glass fiber liner insulations currently being used for such applications. For use as an equipment housing liner and duct liner in HVAC systems, the polymeric fiber liner insulation should have a major surface over which the gases conveyed within the system flow (the airstream surface) that is tough, durable, puncture resistant, smooth and provided with a porosity that reduces sound transmission through the liner. The airstream surface of the liner insulation should be sufficiently tough and durable to resist puncturing and cracking when being handled prior to and during installation to thereby minimize holes on the interior surface of liner that would adversely affect the air flow through the duct and provide a location for dust, dirt particles, bacteria, mold and the like to collect. The airstream surface of the liner insulation should be sufficiently durable to resist erosion when conveying high velocity airstreams and to permit the cleaning of the airstream surface while the liner insulation is in service. The airstream surface of the liner insulation should have a porosity selected to enhance the sound absorption properties of the liner insulation and to minimize locations where dust, dirt particles, bacteria, mold and the like can collect on the airstream surface. The airstream surface of the liner insulation should be smooth to provide an efficient, low operating cost, air conditioning conveying system. In addition, for use as an equipment housing liner and duct liner in HVAC systems, the polymeric fiber liner insulation should exhibit a flame spread index of 25 or less and a smoke developed index of 50 or less as measured in accordance with the ASTM E-84-00a tunnel test (American Society for Testing and Materials E-84-00a tunnel test) entitled xe2x80x9cStandard Test Method for Surface Burning Characteristics of Building Materials. Liner Insulations exhibiting a flame spread index of 25 or less and a smoke developed index of 50 or less, as measured in accordance with the ASTM E-84-00a tunnel test, are hereinafter referred to as having a flame spread/smoke developed index of xe2x89xa625/50.
The resilient liner insulation of the present invention meets or exceeds all of the performance criteria set forth in the background of the invention for a HVAC, equipment housing and duct liner insulation. The resilient liner insulation of the present invention includes a polymeric fiber insulation blanket core. This polymeric fiber insulation blanket core is a coherent mass of randomly oriented entangled polymeric fibers that contains between 60% and 90% by weight standard polymeric staple fibers and/or flame retardant polymeric staple fibers and between 10% and 40% by weight polymeric lofting and bonding fibers.
To minimize locations where dust, dirt particles, bacteria, mold and the like can collect on the resilient liner insulation of the present invention; to provide the resilient liner insulation of the present invention with a tough, durable, puncture resistant, smooth airstream surface for an efficient, low operating cost, air conditioning system; and to provide the resilient liner insulation of the present invention with an enhanced air flow resistance that reduces sound transmission through the liner, the resilient liner insulation of the present invention has a smooth, tough, durable, puncture resistant, low porosity airstream surface. The low porosity airstream surface of the resilient insulation liner is formed on the polymeric fiber insulation blanket core by melting and consolidating polymeric fibers at and adjacent a major surface of the insulation blanket core to form a low porosity surface layer on the major surface of the insulation blanket core or by forming a single or multilayered low porosity acrylic surface coating layer on the major surface of the insulation blanket core. Preferably, the permeability of the surface layer is selected to provide the polymeric fiber liner insulation with a higher noise reduction coefficient than an identical polymeric fiber insulation blanket without the surface layer and preferably, the surface layer of the first major surface of the liner insulation has a porosity of between 200 and 1000 Mks Rayls as measured by ASTM test C522-87.
While the polymeric fiber insulation blanket core of the resilient insulation liner of the present invention may be made with standard polymeric staple fibers and/or flame retardant polymeric staple fibers, it is preferred to form the insulation blanket core with standard polymeric staple fibers which are lower in cost than the flame retardant polymeric staple fibers. As discussed above, to be suitable for use as a HVAC equipment and duct liner insulation, liner insulation should exhibit a flame spread/smoke developed index of xe2x89xa625/50. For the resilient liner insulation of the present invention to exhibit a flame spread/smoke developed index of xe2x89xa625/50, it was initially thought that the resilient liner insulation of the present invention would require a polymeric fiber insulation blanket core having between 40% and 50% by weight flame retardant polymeric staple fibers. However, when both coated and uncoated resilient liner insulations of the present invention having about 80% by weight standard polyester staple fibers and about 20% by weight polyester lofting and bonding fibers were tested, the heat from the flame front on the low porosity major surfaces of these resilient liner insulations caused the polyester fibers at and adjacent these major surfaces to melt and shrink away from the flame front enabling the resilient liner insulations of the present invention to exhibit a flame spread/smoke developed index of xe2x89xa625/50 without the inclusion of flame retardant polymeric staple fibers.
While the resilient liner insulation of the present invention, for use as an equipment and duct liner insulation in an HVAC system, preferably, has a porous major surface designed to increase the air flow resistance through the surface and improve the noise reduction coefficient of the liner, for other applications the surface layer forming this major surface of the resilient liner insulation may be impervious to liquids and/or gases (a fluid impervious layer).